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NBC's changing of the guard at TV's most valuable late-night property happens under very different circumstances than in 2009, as ABC's Kimmel improves in his year-old time slot and cable's portfolio of talkers continues to grow.

Jay Leno is poised to go out on a high note.

The Tonight Show host, who will exit NBC's iconic late-night talker for the second time Feb. 6, leaves the broadcast TV playing field as the de facto ratings victor -- and he's notching new highs as he approaches his final show.

Viewers may sense more than a little deja vu when Leno, 63, officially passes the Tonight torch to Jimmy Fallon, 39 -- after all, it's been just four years since an abrupt end to Conan O'Brien's brief tenure put Leno back at 11:35 p.m. -- but this changing of the guard takes place in a vastly different landscape. In addition to a wider (and younger-skewing) playing field care of more and more late-night talk options on cable (see Bravo's Andy Cohen, TBS' Pete Holmes), ABC shifted its late-night plan in early 2013, moving Jimmy Kimmel, 46, to the 11:35 p.m. time slot previously occupied only by veterans Leno and CBS' David Letterman, 66.

Though NBC, like its rivals, has its eye on demographics, it should be noted that Leno is set to leave Tonight while it's still late night's most valuable property. Though down some 40 percent from half a decade earlier, the NBC franchise continues to out-earn its competitors, delivering more than $125 million in ad revenue in 2013. It attracts the biggest audience, too, with 3.83 million viewers thus far this season, up 8 percent year over year as many of Leno's peers have seen losses.

Of course, the bid for adults 18-49, the demo that advertisers pay a premium to reach, is a more complicated race, which explains, in part, why NBC is passing the Tonight baton to a younger, more digitally savvy host. Though Leno still outranks his broadcast rivals with 1.13 million demo viewers, it is Jimmy Kimmel Live's continued momentum that poses the biggest threat to Tonight's demo reign -- especially now that viewers are faced with the decision of whether or not to stick around when Fallon moves into the hour. With a heavy reliance on taped segments and musical performances, the two Jimmys are arguably the most similar brands in late night. (At 11 p.m., Comedy Central's TheDaily Show With Jon Stewart garners the biggest viewership among that younger set.)

Kimmel's rise, both online and on air, has been impossible to ignore, and undoubtedly factored into NBC's decision to bump Fallon up. Kimmel's first complete season at 11:35 p.m. is now up 28 percent over the previous year, when he ran almost exclusively in the 12:05 a.m. slot. What's more, his 917,000 demo viewership already is outpacing long-tenured Letterman by 162,000 viewers, and is likely a major factor in the latter's 17 percent decline this season. (There's still room for improvement, though: Kimmel's ABC show trails former time slot occupant Nightline's 2012-13 season showing by about 6 percent.)

To be sure, Fallon will enter the more competitive (and crowded) 11:35 p.m. market with a surge of goodwill. Over and above the continued praise from his predecessor -- in an interview with THR, Leno reiterated how he "genuinely" likes Jimmy, whom he suggested was the most like Johnny Carson was when he started -- Fallon's own viewership is up considerably as he prepares to turn the show over to Seth Meyers, 40. With 192,000 adults, on average, under 50, he's up 17 percent season to date, and is blowing every other 12:35 a.m. talk show out of the water.

But while his initial ratings surrounding his Feb. 17 launch will be the subject of much watercooler talk, between the late night media fixation and NBC's inevitable Winter Olympics boost it will be months before his audience is indicative of any long-term trend.